This invention relates to training cups for toddlers and more particularly comprises a spill proof training cup.
There are presently available a number of so called xe2x80x9cno spillxe2x80x9d training cups for toddlers. As the name implies, these cups are intended to prevent liquid spilling from the cups when they are inverted or dropped. Ideally, the only way liquid can be withdrawn from such cups other than by removing their covers and pouring out the contents is by a toddler sucking on the drinking spout of a cup. The prior art products on the market perform with varying degrees of success, and many are relatively expensive to manufacture. Examples of the prior art are shown in U.S. Pat. Nos. 2,876,772; 3,967,748; 4,135,513; 4,836,404; 4,946,062; 5,050,758; 5,079,013; 5,186,347; 5,339,982; 5,542,670; 5,607,073; 5,706,973; 5,890,621; GB2,169,210; GB2,266,045; EP0634,922.
The training cup in accordance with one aspect of this invention has a detachable lid with a drinking spout extending upwardly therefrom. A valve assembly including a housing is mounted on the inner side of the lid in communication with the inlet end of the spout so that liquid to be drawn through the spout must flow through the housing. In accordance with another aspect of this invention the valve assembly includes a diaphragm valve in and supported by the housing and biased to a closed position. The diaphragm valve remains closed unless the pressure on the outlet side of the diaphragm is less than the pressure on the inlet side thereof. In accordance with another aspect of the invention, the diaphragm may be inexpensively made of a thin silicon wafer approximately 0.040 inch in thickness that may be extruded in sheet form and simply stamped from the sheet in the size and shape desired. In accordance with yet another aspect of the invention a strap is connected to the valve housing and is separately attached to the lid so that the housing can be separated from the spout while the strap remains attached to the lid so that it will not be lost or misplaced.
In accordance with yet another aspect of the invention, the vent hole in the lid is closed by a hydrophobic membrane that allows air to enter the cup through the hole but prevents liquid from flowing out of the cup through the hole.
The invention will be better understood and appreciated from the following detailed description read in conjunction with the accompanying drawings.